Power supply circuit and display device including the same

Abstract

A display apparatus includes a display panel configured to display an image, a driver configured to drive the display panel, and a power supply including an output circuit configured to charge or discharge power input through an input terminal thereof to output through an output terminal thereof and an output controller configured to control charging or discharging of the output circuit, for supplying power to the display panel, wherein the output controller operates in one of a first driving mode of operating with a first switching frequency and a second driving mode of operating with a second switching frequency which is higher than the first switching frequency.

1 . A display apparatus comprising:
 a display panel configured to display an image;   a driver configured to drive the display panel; and   a power supply circuit for supplying power to the display panel, the power supply circuit including an output circuit and an output controller, the output circuit configured to charge or discharge a power input through an input terminal thereof and to output an power output through an output terminal thereof, and the output controller configured to control charging or discharging of the output circuit,   wherein the output controller is configured to operate in one of a first driving mode of operating with a first switching frequency and a second driving mode of operating with a second switching frequency that is higher than the first switching frequency.   
     
     
         2 . The display apparatus of  claim 1 , wherein the output controller sets the second driving mode to a higher-priority driving mode. 
     
     
         3 . The display apparatus of  claim 1 , wherein the driving mode of the output controller is determined according to output efficiency of the output circuit and noise. 
     
     
         4 . The display apparatus of  claim 1 , wherein the output controller comprises:
 a signal generator configured to generate a switch signal for controlling an on/off switching timing of each of switches included in the output circuit;   an efficiency calculator configured to calculate an efficiency calculation result value, based on an input current value flowing through the input terminal of the output circuit and an output current value flowing through the output terminal of the output circuit;   a mode controller configured to generate a mode control value, based on the efficiency calculation result value provided from the efficiency calculator and a mode setting result value provided based on a mode setting value set by an external input and a peak-to-peak voltage value provided in the output terminal of the output circuit; and   a signal controller configured to generate a signal for controlling the signal generator, based on a sensing value obtained by sensing a voltage output through the output terminal of the output circuit, an inductor current value output through an inductor of the output circuit, and the mode control value output from the mode controller.   
     
     
         5 . The display apparatus of  claim 4 , wherein the efficiency calculator comprises:
 a divider configured to perform a division operation so that the input current value and the output current value are selectively charged in a first capacitor and a second capacitor and are stored as efficiency values; and   a first comparator configured to compare the efficiency values charged in the first capacitor and the second capacitor to generate the efficiency calculation result value.   
     
     
         6 . The display apparatus of  claim 5 , wherein the mode controller comprises:
 a second comparator configured to compare the peak-to-peak voltage value with the mode setting value to generate the mode setting result value;   an inverter configured to invert and output the mode setting result value output from the second comparator; and   an AND gate configured to perform an AND operation on the mode setting result value inverted and output by the inverter and the efficiency calculation result value output from the efficiency calculator to generate an operation result value.   
     
     
         7 . The display apparatus of  claim 6 , wherein the signal controller comprises:
 a first resistor and a second resistor serially connected between the output terminal of the output circuit and a ground terminal;   a third comparator configured to compare a reference voltage, obtained through a reference voltage terminal, with the sensing value obtained through a node between the first resistor and the second resistor to generate a first comparison result value;   a fourth comparator configured to compare the inductor current value with the first comparison result value output from the third comparator to generate a second comparison result value;   an oscillator configured to operate to generate a pulse value, based on the mode setting result value output from the second comparator of the mode controller and the operation result value output from the AND gate of the mode controller; and   a fifth comparator configured to compare the second comparison result value, output from the fourth comparator, with the pulse value output from the oscillator to generate a control signal for controlling the signal generator.   
     
     
         8 . A power supply circuit comprising:
 an output circuit configured to charge or discharge power input through an input terminal thereof and to output a power output through an output terminal thereof; and   an output controller configured to control charging or discharging of the output circuit,   wherein the output controller operates in one of a first driving mode of operating with a first switching frequency and a second driving mode of operating with a second switching frequency that is higher than the first switching frequency.   
     
     
         9 . The power supply of  claim 8 , wherein the output controller sets the second driving mode to a higher-priority driving mode. 
     
     
         10 . The power supply of  claim 8 , wherein the driving mode of the output controller is determined according to output efficiency of the output circuit and noise. 
     
     
         11 . The power supply of  claim 8 , wherein the output controller comprises:
 a signal generator configured to generate a switch signal for controlling an on/off switching timing of each of switches included in the output circuit;   an efficiency calculator configured to calculate an efficiency calculation result value, based on an input current value flowing through the input terminal of the output circuit and an output current value flowing through the output terminal of the output circuit;   a mode controller configured to generate a mode control value, based on the efficiency calculation result value provided from the efficiency calculator and a mode setting result value provided based on a mode setting value set by an external input and a peak-to-peak voltage value provided in the output terminal of the output circuit; and   a signal controller configured to generate a signal for controlling the signal generator, based on a sensing value obtained by sensing a voltage output through the output terminal of the output circuit, an inductor current value output through an inductor of the output circuit, and the mode control value output from the mode controller.   
     
     
         12 . The power supply of  claim 11 , wherein the efficiency calculator comprises:
 a divider configured to perform a division operation so that the input current value and the output current value are selectively charged in a first capacitor and a second capacitor and are stored as efficiency values; and   a first comparator configured to compare the efficiency values charged in the first capacitor and the second capacitor to generate the efficiency calculation result value.   
     
     
         13 . The power supply of  claim 12 , wherein the mode controller comprises:
 a second comparator configured to compare the peak-to-peak voltage value with the mode setting value to generate the mode setting result value;   an inverter configured to invert and output the mode setting result value output from the second comparator; and   an AND gate configured to perform an AND operation on the mode setting result value inverted and output by the inverter and the efficiency calculation result value output from the efficiency calculator to generate an operation result value.   
     
     
         14 . The power supply of  claim 13 , wherein the signal controller comprises:
 a first resistor and a second resistor serially connected between the output terminal of the output circuit and a ground terminal;   a third comparator configured to compare a reference voltage, obtained through a reference voltage terminal, with the sensing value obtained through a node between the first resistor and the second resistor to generate a first comparison result value;   a fourth comparator configured to compare the inductor current value with the first comparison result value output from the third comparator to generate a second comparison result value;   an oscillator configured to operate to generate a pulse value, based on the mode setting result value output from the second comparator of the mode controller and the operation result value output from the AND gate of the mode controller; and   a fifth comparator configured to compare the second comparison result value, output from the fourth comparator, with the pulse value output from the oscillator to generate a control signal for controlling the signal generator.